Severe viral infection and the kidney: lessons learned from the H1N1 pandemic

Influenza A virus replicates productively in primary human kidney cells and induces factors and mechanisms related to regulated cell death and renal pathology observed in virus-infected patients

Introduction

Influenza A virus (IAV) infection can cause the often-lethal acute respiratory distress syndrome (ARDS) of the lung. Concomitantly, acute kidney injury (AKI) is frequently noticed during IAV infection, correlating with an increased mortality. The aim of this study was to elucidate the interaction of IAV with human kidney cells and, thereby, to assess the mechanisms underlying IAV-mediated AKI.

Methods

To investigate IAV effects on nephron cells we performed infectivity assays with human IAV, as well as with human isolates of either low or highly pathogenic avian IAV. Also, transcriptome and proteome analysis of IAV-infected primary human distal tubular kidney cells (DTC) was performed. Furthermore, the DTC transcriptome was compared to existing transcriptomic data from IAV-infected lung and trachea cells.

Results

We demonstrate productive replication of all tested IAV strains on primary and immortalized nephron cells. Comparison of our transcriptome and proteome analysis of H1N1-type IAV-infected human primary distal tubular cells (DTC) with existing data from H1N1-type IAV-infected lung and primary trachea cells revealed enrichment of specific factors responsible for regulated cell death in primary DTC, which could be targeted by specific inhibitors.

Discussion

IAV not only infects, but also productively replicates on different human nephron cells. Importantly, multi-omics analysis revealed regulated cell death as potential contributing factor for the clinically observed kidney pathology in influenza.

Pathophysiology of COVID-19-associated acute kidney injury

Although respiratory failure and hypoxaemia are the main manifestations of COVID-19, kidney involvement is also common. Available evidence supports a number of potential pathophysiological pathways through which acute kidney injury (AKI) can develop in the context of SARS-CoV-2 infection. Histopathological findings have highlighted both similarities and differences between AKI in patients with COVID-19 and in those with AKI in non-COVID-related sepsis. Acute tubular injury is common, although it is often mild, despite markedly reduced kidney function. Systemic haemodynamic instability very likely contributes to tubular injury. Despite descriptions of COVID-19 as a cytokine storm syndrome, levels of circulating cytokines are often lower in patients with COVID-19 than in patients with acute respiratory distress syndrome with causes other than COVID-19. Tissue inflammation and local immune cell infiltration have been repeatedly observed and might have a critical role in kidney injury, as might endothelial injury and microvascular thrombi. Findings of high viral load in patients who have died with AKI suggest a contribution of viral invasion in the kidneys, although the issue of renal tropism remains controversial. An impaired type I interferon response has also been reported in patients with severe COVID-19. In light of these observations, the potential pathophysiological mechanisms of COVID-19-associated AKI may provide insights into therapeutic strategies.

Prognostic Implications of Preoperative Pneumonia for Geriatric Patients Undergoing Hip Fracture Surgery or Arthroplasty

Objective

To report outcomes of geriatric patients undergoing hip fracture surgery or arthroplasty with or without preoperative pneumonia and to evaluate the influence of pneumonia severity on patient prognosis.

Methods

In this single center retrospective study, we included geriatric patients (≥60 years old) who had undergone hip fracture surgery or arthroplasty at Peking University People's Hospital from January 2008 to September 2018. Patients with fractures caused by neoplasms or patients with incomplete clinical data were excluded. Using logistic regression and the CURB‐65 (confusion, uremia, respiratory rate, blood pressure, and age ≥65 years) score as a prediction tool of 1‐year mortality, the effect of preoperative pneumonia on 1‐year mortality was evaluated. Survival of patients with different response to pneumonia‐specific therapy and survival of patients with different pneumonia severity (evaluated with CURB‐65 score) were analyzed using Cox regression.

Results

A total of 1386 patients were included; among them, 109 patients (7.86%) were diagnosed with preoperative pneumonia. Outcomes were evaluated in August 2019 (at least 1 year after surgery for all patients). Compared to patients without preoperative pneumonia, patients with this condition had higher 30‐day mortality (11.9% vs 5%, P = 0.002) and 1‐year mortality rates (33.9% vs 16.3%, P < 0.001) and higher incidence of acute heart failure (7.3% vs 3.4%, P = 0.034) and acute kidney injury (5.5% vs 1.8%, P = 0.009). In multivariate regression, preoperative pneumonia was identified as an independent predictor of 1‐year mortality (odds ratio [OR], 1.45; 95% confidence interval [CI] 1.39–3.52; P = 0.021), with other factors including age (≥84 years, OR, 1.46; 95% CI 1.08–1.60; P = 0.027), body mass index (<18.5 kg/m², OR 2.23; 95% CI 1.52–3.17, P < 0.001), anesthesia type (regional, OR 0.87; 95% CI 0.19–0.97, P = 0.042), preoperative pneumonia (OR 1.45; 95% CI 1.39–3.52; P = 0.002), congestive heart failure (OR 2.05, 95% CI 1.57–6.21, P < 0.001), chronic kidney disease (OR 1.73; 95% CI 1.50–2.62; P < 0.001). There was a trend of increased 1‐year mortality as the CURB‐65 score elevated (P for trend = 0.006). Cox regression reveals a higher risk of mortality in patient with preoperative pneumonia, especially in patients with no radiologic improvements after therapy (log‐rank, P = 0.035). Analysis of the impact of pneumonia severity on patient survival using Cox regression reveals that a CURB‐65 score ≥3 indicated a lower rate of survival (CURB‐65 score of 3: hazard ratio [HR] 3.12, 95% CI 1.39–7.03, P = 0.006; score of 4: HR 3.41, 95% CI 1.69–6.92, P = 0.001; score of 5: HR 6.28, 95% CI 2.95–13.35, P < 0.001).

Conclusion

In this single center retrospective study, preoperative pneumonia was identified as an independent risk factor of 1‐year mortality in geriatric patients undergoing hip fracture surgery or arthroplasty. A CURB‐65 score ≥3 indicated a higher risk of mortality.

Influenza in hospitalised patients with malignancy: a propensity score matching analysis

Background

Patients with malignancy are vulnerable to influenza viruses and are at high risk of developing serious complications. However, few studies have investigated the impact of influenza infection among hospitalised patients with malignancy.

Methods

Cancer-related hospitalisations were identified by using data from National Inpatient Sample in the USA between 2012 and 2014. We conducted a 1:1 propensity score matching analysis to compare the in-hospital outcomes between cancer patients with and without influenza. Multivariate logistic regression analyses were also performed to identify independent prognosis predictors of mortality.

Results

We identified 13 186 849 weighted cancer-related hospitalisations during the study period, and 47 850 of them (0.36%) had a concomitant diagnosis of influenza. After propensity score matching, cancer patients with concomitant influenza had a higher mortality (5.4% vs 4.2%; OR, 1.30; 95% CI, 1.13 to 1.49; p<0.001), longer length of stay (6.3 days vs 5.6 days; p<0.001) but lower costs (US$14 605.9 vs US$14 625.5; p<0.001) in hospital than those without influenza. In addition, cancer patients with influenza had a higher incidence of complications, including pneumonia (18.4% vs 13.2%; OR, 1.49; 95% CI, 1.37 to 1.62; p<0.001), neutropenia (7.1% vs 3.4%; OR, 2.18; 95% CI, 1.91 to 2.50; p<0.001), sepsis (19.5% vs 9.3%; OR, 2.36; 95% CI, 2.16 to 2.58; p<0.001), dehydration (14.8% vs 8.8%; OR, 1.80; 95% CI, 1.65 to 1.97; p<0.001) and acute kidney injury (19.9% vs 17.6%; OR, 1.16; 95% CI, 1.08 to 1.25; p<0.001) than those without influenza. Older age, no insurance, more comorbidities, lung cancer and haematological malignancy were independently associated with higher mortality.

Conclusion

Influenza is associated with worse in-hospital clinical outcomes among hospitalised patients with malignancy. Annual influenza vaccination and early initiation of antiviral therapy are recommended in this high-risk population.

The Incidence, Risk Factors, and Prognosis of Acute Kidney Injury in Adult Patients with Coronavirus Disease 2019

BACKGROUND AND OBJECTIVES

Since December 2019, coronavirus disease 2019 (COVID-19) outbreak occurred and has rapidly spread worldwide. However, little information is available about the AKI in COVID-19. We aimed to evaluate the incidence, risk factors, and prognosis of AKI in adult patients with COVID-19.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a retrospective cohort study of 1392 patients with COVID-19 admitted to a tertiary teaching hospital. Clinical characteristics and laboratory data were extracted from electronic hospitalization and laboratory databases. AKI was defined and staged according to the 2012 Kidney Disease: Improving Global Outcomes criteria. Risk factors for AKI and the association of AKI with in-hospital mortality were assessed.

RESULTS

A total of 7% (99 of 1392) of patients developed AKI during hospitalization, 40% (40 of 99) of which occurred within 1 week of admission. Factors associated with a higher risk of AKI include severe disease (odds ratio [OR], 2.25; 95% confidence interval [CI], 1.37 to 3.67), higher baseline serum creatinine (OR, 2.19; 95% CI, 1.17 to 4.11), lymphopenia (OR, 1.99; 95% CI, 1.12 to 3.53), and elevated D-dimer level (OR, 2.68; 95% CI, 1.07 to 6.70). The in-hospital mortality in patients with AKI stage 1, stage 2, and stage 3 was 62%, 77%, and 80%, respectively. AKI was associated with in-hospital mortality even after adjustment for confounders (OR, 5.12; 95% CI, 2.70 to 9.72).

CONCLUSIONS

AKI is uncommon but carries high in-hospital mortality in patients with COVID-19.